A wiring structure and a wiring method for a large AGV vehicle body substrate

Abstract

The application discloses a kind of multi-channel bus wiring structure and wiring method for large AGV car body substrate, comprising: substrate, a plurality of nodes are arranged in array on substrate, and the plurality of nodes are divided into a plurality of functional groups in continuous piece;Multi-channel bus is arranged on the substrate, each bus is connected with main controller respectively, and each functional group includes several buses;Anti-interference unit is arranged on each bus, and the anti-interference unit can isolate the interference of bus;Wherein, each bus includes main line and branch line, and the wiring of main line is serpentine path;Branch line is accessed to main line through each node in each functional group.The application does not need to additionally increase repeater or concentrator, reduces system cost and complexity.And, greatly simplify the wiring process.At the same time, the application also uses the interference shielding capacity of anti-interference unit, realizes the stable and reliable communication of multi-channel bus, and does not interfere with each other.

Description

Technical Field

[0001] This invention relates to the field of electrical wiring technology for automated guided vehicles, and in particular to a wiring structure and wiring method for a large AGV body base plate. Background Technology

[0002] With the development of industrial automation and intelligent logistics, AGVs (Automated Guided Vehicles) are evolving towards larger sizes and more multifunctionality. Modern large AGVs (e.g., with dimensions of 2.1m × 2.1m) typically require a large number of actuators and sensor nodes, such as support mechanism controllers, indicator lights, power switches, position sensors, and obstacle avoidance sensors, with the total number of nodes exceeding 100. These nodes need to interact with the main controller via a fieldbus.

[0003] RS485 bus is widely used for interconnecting internal devices in AGVs due to its advantages such as differential transmission, immunity to common-mode interference, support for multiple nodes, and long-distance communication. However, the RS485 standard specifies that a single bus segment can connect a maximum of 32 unit loads. When the number of nodes exceeds 32, multi-bus segmentation or the use of repeaters / hubs for expansion must be adopted. Simultaneously deploying multiple RS485 buses inside the AGV body will face problems such as space constraints, high wiring complexity, and strong electromagnetic interference environment. Summary of the Invention

[0004] Therefore, it is necessary to provide a wiring structure and wiring method for a large AGV vehicle body base plate to address the above-mentioned technical problems.

[0005] A multi-bus wiring structure for a large AGV body base plate includes: A substrate having multiple nodes arranged in an array on it, the multiple nodes being divided into several functional groups that are continuously arranged in a sheet. Multiple buses are disposed on the substrate, each bus is connected to the main controller, and each functional group includes several buses; An anti-interference unit is provided on each of the buses, and the anti-interference unit enables the buses to isolate interference. Each of the bus paths includes a main line and branch lines, with the main line following a serpentine path; the branch lines connect to the main line via each node within each of the functional groups.

[0006] In one embodiment, the functional group includes a support control group and an indicator power group, each of the buses in the support control group and the indicator power group being independently wired.

[0007] In one embodiment, the serpentine path includes: the main line is laid along one row of the substrate to the edge of the functional group and then turns back, is laid in the opposite direction along the adjacent row, and sequentially covers all node positions of the bus.

[0008] In one embodiment, the main line and the branch line are connected by welding or by a T-type dedicated connector.

[0009] In one embodiment, the main line and branch line are shielded twisted pair cables, and the shielding layer of the shielded twisted pair cable is a double layer of aluminum foil and braided mesh shielding.

[0010] In one embodiment, the anti-interference unit: Termination resistors are set at the physical start and physical end of each of the aforementioned buses; Bias resistors are set at the host end of each of the buses, and the host end is connected to the main controller; An electrical isolation module is installed at each node of the bus.

[0011] In one embodiment, the different buses are placed in independent slots or in cavities separated by metal partitions in the same slot, and the slot spacing between adjacent buses is not less than 10 mm.

[0012] A wiring method for a multi-bus wiring structure for a large AGV body base plate includes the following steps: S1. Divide the nodes on the substrate into several functional groups; S2. Plan the serpentine path for each bus in each of the aforementioned functional groups; S3. Connect each branch line of the bus to the main line; S4. Install terminating resistor.

[0013] In one embodiment, the substrate is provided with a power harness, and the distance between the bus and the power harness is not less than 30cm.

[0014] In one embodiment, the bus is an RS485 bus, and the support control group and the indicator power group of the functional group each include three RS485 buses.

[0015] The aforementioned wiring structure and method for the large AGV chassis base plate divides multiple nodes into several continuous functional groups. Each functional group includes several buses, and the load capacity of each bus conforms to standard specifications while fully utilizing the multi-point capability of the RS485 bus. This eliminates the need for additional repeaters or hubs, reducing system cost and complexity. Furthermore, the buses are laid in a serpentine pattern on the bottom of the chassis base plate, eliminating the need to cut the main lines during on-site installation; branch lines are simply connected at the node locations, greatly simplifying the wiring process. Simultaneously, this invention utilizes the interference shielding capability of the anti-interference unit to achieve stable, reliable, and non-interfering communication among multiple buses. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the multi-bus wiring structure for a large AGV body base plate of the present invention; Figure 2 This is a partial structural diagram of the single-channel bus of the present invention; Figure 3 This is a schematic diagram of the structure of the parallel laying section of the multi-bus according to the present invention; Figure 4 This is a block diagram of the internal isolation module connection of the node device of the present invention; Figure 5 This is a hardware block diagram of the multi-channel RS485 interface of the AGV main controller of the present invention. Detailed Implementation

[0018] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0019] It should be noted that when a component is said to be "fixed to" another component, it can be directly attached to the other component or there may be an intervening component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Example

[0021] See Figure 1-5 As shown, an embodiment of the present invention provides a multi-bus wiring structure for a large AGV vehicle body base plate, including a base plate 1, a multi-bus 3 and an anti-interference unit 4.

[0022] The substrate 1 has multiple nodes 2 arranged in an array, and the multiple nodes 2 are divided into several functional groups in a continuous sheet; in this embodiment, the AGV vehicle body substrate 1 has a total of N nodes (N=96), which are arranged in an M×K array (e.g., 10×10 or 200×200 grid).

[0023] Multiple buses 3 are disposed on the substrate 1, each of the buses 3 is connected to the main controller, and each functional group includes several buses 3; in this embodiment, the bus 3 can be an RS485 bus, and in some embodiments, the bus 3 can also be other types of buses.

[0024] An anti-interference unit 4 is provided on each of the bus 3, and the anti-interference unit 4 enables the bus 3 to isolate interference. Each of the bus paths 3 includes a main line 31 and a branch line 32. The main line 31 is routed in a serpentine path. The branch line 32 is connected to the main line 31 through each of the nodes 2 in each of the functional groups.

[0025] The aforementioned wiring structure and method for the large AGV chassis base plate 1 divides multiple nodes 2 into several continuous functional groups. Each functional group includes several buses 3. The load capacity of each bus 3 not only conforms to standard specifications but also fully utilizes the multi-point capability of the RS485 bus, eliminating the need for additional repeaters or hubs, thus reducing system cost and complexity. Furthermore, the buses 3 are laid in a serpentine pattern at the bottom of the chassis base plate, eliminating the need to cut the main lines during on-site construction. Only branch lines 32 need to be connected at node 2, greatly simplifying the wiring process. Simultaneously, this invention utilizes the interference shielding capability of the anti-interference unit 4 to achieve stable, reliable, and non-interfering communication among the multiple buses 3.

[0026] In one embodiment of the present invention, the functional group includes a support control group and an indicator power group, and each bus 3 of the support control group and the indicator power group is independently wired. In this embodiment, the support control group and the indicator power group each include three RS485 buses. Specifically, the support control group is divided into three buses: bus A1, bus A2, and bus A3, each carrying 32 nodes. The indicator power group is divided into three buses: bus B1, bus B2, and bus B3, each carrying 32 nodes, for a total of six RS485 buses. Each RS485 bus is independently wired and does not intersect with each other. Each RS485 bus is connected to the corresponding RS485 interface on the main controller. It should be noted that the support control group mainly consists of support control nodes, and the indicator power group mainly consists of indicator light / power switch nodes.

[0027] In one embodiment of the present invention, the serpentine path includes: the main line 31 is laid along one row of the substrate 1 to the edge of the functional group and then turns back, is laid in the opposite direction along the adjacent row, and sequentially covers all node 2 positions of the bus 3. In this embodiment, each bus 3 adopts a serpentine (S-shaped) routing, so that all nodes 2 can be covered in a limited space and the length of the bus 3 can be reduced.

[0028] In one embodiment of the present invention, the main line 31 and the branch line 32 are connected by welding or by a T-type dedicated connector. In this embodiment, the main line 31 and the branch line 32 do not use piercing connection, and the length of the branch line 32 is controlled within 0.3 meters (since the array node spacing is usually 200mm, the branch line can be led vertically from the main line laying path to the node, and the length can be controlled within 0.2 meters). It should be noted that the serpentine arrangement minimizes the total length of the main line 3, and at the same time, facilitates the branch line 32 to be connected to the position of each node 2 in the array with a very short distance.

[0029] In one embodiment of the present invention, the main line 31 and the branch line 32 are shielded twisted-pair cables, and the shielding layer of the shielded twisted-pair cables is a double layer of aluminum foil and braided mesh shielding. Specifically, both the main line 31 and the branch line 32 use shielded twisted-pair cables with a characteristic impedance of 120Ω and a wire diameter of 0.5mm² or 0.75mm². It should be noted that the shielding layer of the main line 31 of each bus 3 remains continuous during the laying process, and the shielding layer of the branch line 32 overlaps with the shielding layer of the main line 31 at the connection point. The shielding layer of the entire bus is grounded at only one point (single-point grounding), and the grounding location is selected at the AGV main controller end, connected to a reliable grounding point of the vehicle body metal substrate. In this way, the single-point grounding scheme can eliminate the ground loop formed by multiple grounding points, completely eliminating the common-mode interference caused by the ground loop. Combined with a complete and continuous double-layer shielding structure, a complete electromagnetic protection system is built from three dimensions: cable selection, shielding connection, and grounding method. This ensures stable communication of multiple RS485 buses in the strong electromagnetic environment of large AGVs, and avoids crosstalk between buses, data packet loss, bit errors and other faults.

[0030] In one embodiment of the present invention, the anti-interference unit 4: Termination resistors are installed at the physical beginning and end of each of the aforementioned bus 3. Specifically, a 120Ω±1% termination resistor is connected in parallel at both the physical beginning (AGV main controller end) and the physical end (the farthest node in the serpentine cabling of each bus 3), while no termination resistors are installed at intermediate nodes. This configuration matches the characteristic impedance of the shielded twisted pair cable, eliminates signal transmission reflection and waveform ringing, prevents signal distortion during long-distance transmission across multiple nodes, and avoids exceeding the bus load limit due to parallel resistors at multiple locations.

[0031] A bias resistor is set at the host end of each of the aforementioned bus 3, which is connected to the main controller. In this embodiment, the RS485 bus includes line A and line B. A bias resistor is only set at the host end of each of the aforementioned bus 3 (the interface corresponding to the AGV main controller): line A is pulled up to the power supply (3.3V or 5V, resistance value 680Ω~1kΩ), and line B is pulled down to ground (same resistance value). No bias resistor is set at intermediate nodes. In this way, the idle differential level of the bus can be fixed, the coupling noise of the power cable can be suppressed to prevent the receiver from being mistakenly triggered, and the arrangement is only required at the main control end, simplifying the hardware of each node and reducing the overall material and wiring costs.

[0032] An electrical isolation module is installed at each node 2 of the bus 3. The requirements for the electrical isolation module are: isolation withstand voltage ≥2500VDC, common-mode transient suppression capability ≥25kV / μs. Integrated isolated RS-485 transceiver modules can be used. In this invention, the high isolation withstand voltage of the electrical isolation module can cut off ground loops between different nodes in the vehicle body, eliminating common-mode interference caused by ground potential differences; the strong transient suppression capability can withstand high-voltage spike surges generated by the switching of motors and solenoid valves, achieving electrical isolation between the node and the bus. A single node failure will not back-impact the main control interface, avoiding paralysis of the entire bus communication.

[0033] Optionally, the communication baud rate of each bus 3 is limited to less than or equal to 9600bps, preferably less than or equal to 4800bps, to reduce the effects of branch reflections and crosstalk.

[0034] In one embodiment of the present invention, different buses 3 are placed in independent slots or in cavities separated by metal partitions within the same slot, and the spacing between adjacent bus slots is not less than 10 mm. This is to avoid crosstalk between buses 3.

[0035] An embodiment of the present invention provides a wiring method for a multi-bus 3 wiring structure for a large AGV body base plate 1, comprising the following steps: S1. Divide the nodes 2 on the substrate 1 into several functional groups. In this embodiment, the multiple nodes of the 200mm×200mm grid array are divided into multiple functional groups. The nodes of each functional group are physically connected in a continuous sheet to facilitate the coverage of the serpentine bus.

[0036] S2. Plan the serpentine path for each bus 3 in each functional group; specifically, for each bus 3, determine the range of nodes 2 it covers. Assuming that the bus 3 covers 4 rows × 5 columns = 20 nodes, the serpentine path is as follows: starting from the main controller, it is laid along the first row in the X direction at the bottom of the substrate 1, passing through all nodes 2 in that row, and after reaching the end of the row, it turns back and is laid in the reverse direction along the second row, and so on, until all nodes 2 are covered. The turning radius at the turn points between each row must ensure the minimum bending radius of the cable (≥ 5 times the wire diameter).

[0037] S3. Connect the branch line 32 of each bus 3 to the main line 31; the length of the branch line 32 is controlled between 0.15 and 0.25 meters (just enough to be led vertically upward or laterally from the main line slot to the node junction box).

[0038] S4. Termination resistor installation. At the physical furthest node of the serpentine path (i.e., the last node after the last turnaround), connect a termination resistor in parallel to the front end of the electrical isolation module of that node. The first termination resistor is located at the RS485 interface of the main controller.

[0039] In one embodiment of the present invention, a power harness is provided on the substrate 1, and the distance between the bus 3 and the power harness is not less than 30cm. In this embodiment, the power harness can be a battery power supply line, a three-phase line of a walking motor driver, a lifting motor line, etc. Preferably, the minimum distance between the communication bus and the power harness is 30cm, and they must not be laid in the same slot. When crossing is unavoidable, the crossing angle should be ≥90°, and a metal partition or metal pipe should be used to shield and protect the communication bus. The power harness uses a shielded power cable, and its shielding layer is grounded at both ends to suppress interference radiation from the source.

[0040] It should be noted that the main controller is configured with at least six independent RS485 interfaces. Each interface has an independent transceiver, configurable terminating resistor, optional bias resistor, and supports independent control of transmit and receive enable. The output signal of each interface is isolated before being sent to the A and B lines of the corresponding bus to achieve electrical isolation between buses and prevent a failure or interference on one bus from affecting other buses.

[0041] In summary, the present invention also has the following advantages: 1. High-capacity node support: By rationally dividing multiple nodes into 6 RS485 buses, each bus can carry no more than 32 nodes. This not only complies with the standard specifications but also makes full use of the multi-point capability of the RS485 bus. There is no need to add repeaters or hubs, which reduces system cost and complexity.

[0042] 2. High ease of construction: Each bus adopts a serpentine layout along the bottom of the substrate, eliminating the need to cut the main line during on-site construction. Only branch lines need to be welded at the node locations. The serpentine path minimizes the total length of the main line and makes the branch lines extremely short (≤0.3m), greatly simplifying the wiring process.

[0043] 3. Strong anti-interference capability: Node-level full isolation can cut off ground loops and suppress common-mode interference; shielded twisted-pair cables plus single-point grounding can suppress electric and magnetic field coupling; terminal resistor matching plus bias resistors can eliminate reflections and ensure stability in idle state; metal tubes / partitions can provide additional electromagnetic shielding; physical separation of multiple buses plus time-division communication can avoid crosstalk between buses. The above measures work together to enable the system to maintain stable communication even in the strong electromagnetic interference environment generated by high-power equipment such as AGV walking motors and lifting motors.

[0044] 4. High space utilization: Utilizing the space under the AGV chassis base plate, multiple bus lines are laid in a serpentine pattern within the cable trays, with branch nodes short-circuited. The overall wiring is compact and orderly, facilitating maintenance and expansion. Simultaneously, the metal partitions in the cable trays also serve a shielding function.

[0045] 5. Maintenance and Expansion Friendly: Not cutting the main line means that if any node fails, simply disconnecting the branch line of that node is sufficient to isolate the fault, without affecting communication between other nodes on the entire bus. When adding a new node, simply add a branch line at an appropriate location on the main line; no rewiring is required.

[0046] 6. Controllable cost: Compared with solutions using industrial Ethernet or CAN bus with repeaters, this invention is based on mature RS485 technology and only requires shielded twisted pair cables, isolation modules and passive resistor networks, which has a significant cost advantage in large-scale production. Example

[0047] Scene parameters: AGV body shape: 2.1m × 2.1m, metal base plate. Total number of nodes: 96, arranged in a 10×10 array, with no nodes at the four corners, array spacing 200mm. Node types: 96 support control nodes (including solenoid valves and motor controllers), 96 indicator / power switch nodes. Power harness: The walking motor driver (3kW) harness is laid along one edge of the base plate, approximately 200mm from the nearest point to the communication bus.

[0048] Bus partitioning: The support control nodes are divided into 3 buses: S1 (32 nodes), S2 (32 nodes), and S3 (32 nodes). Indicator / power nodes are divided into 3 buses: L1 (32 nodes), L2 (32 nodes), and L3 (32 nodes). Single bus wiring parameters (taking S1 as an example): The serpentine routing path (S1 path) covers the fourth node of rows 1-4 of the array, with 8 nodes in the first row, 10 nodes in the second row, 10 nodes in the third row, and 4 nodes in the fourth row, for a total of 32 nodes. Starting from the main controller (located on the left edge of the substrate), the main line is laid from left to right along the first row, passing through the T-shaped lead-out points of 8 nodes. After reaching the right end of the first row, it turns back (bending radius 50mm) and is laid from right to left along the second row, passing through the remaining 8 nodes. The leftmost node in the second row is the physical end, with a 120Ω terminating resistor connected in parallel to its isolation module front end.

[0049] The main controller uses time-division polling communication for S1, S2, S3, L1, L2, and L3, with each bus occupying an independent time slot (e.g., switching one channel every 10ms) to avoid simultaneous transmission and reception.

[0050] Performance verification: When the AGV travels at a speed of 1.5m / s and reaches the designated position, with the supporting fixture working simultaneously, the communication error rate of the 6-channel bus is tested to be less than 10%. -6 This meets the control requirements. Example

[0051] To address the issue of strong electromagnetic radiation in certain AGV operating environments (such as welding workshops or near high-power frequency converters), the following modifications are made to Example 2: All communication harnesses (including all main bus lines) are laid in galvanized steel pipes with a thickness ≥1.5mm. The steel pipes are grounded to the vehicle body base plate every 1m. Branch lines are led out of the steel pipes and covered with a metal braided mesh, with both ends of the mesh grounded to the steel pipe and the node shell, respectively. The bias resistance of each bus is reduced to 470Ω to enhance idle state immunity. The communication rate is reduced to 2400bps. Common-mode chokes (such as TDK ZJYS81R5-2PL51T) are added to the interfaces between the main controller and each bus.

[0052] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0053] The embodiments described above merely illustrate several implementations of the present invention and should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this patent should be determined by the appended claims.

Claims

1. A multi-bus wiring structure for a large AGV vehicle body base plate, characterized in that, include: A substrate having multiple nodes arranged in an array on it, the multiple nodes being divided into several functional groups that are continuously arranged in a sheet. Multiple buses are disposed on the substrate, each bus is connected to the main controller, and each functional group includes several buses; An anti-interference unit is provided on each of the buses, and the anti-interference unit enables the buses to isolate interference. Each of the bus paths includes a main line and branch lines, with the main line following a serpentine path; the branch lines connect to the main line via each node within each of the functional groups.

2. The multi-bus wiring structure for a large AGV body base plate as described in claim 1, characterized in that, The functional group includes a support control group and an indicator power group, with each bus of the support control group and the indicator power group being independently wired.

3. The multi-bus wiring structure for a large AGV vehicle body base plate as described in claim 2, characterized in that, The serpentine path includes: the main line is laid along one row of the substrate to the edge of the functional group and then turns back, is laid in the opposite direction along the adjacent row, and sequentially covers all node positions of the bus.

4. The multi-bus wiring structure for a large AGV vehicle body base plate as described in claim 1, characterized in that, The main line and the branch line are connected by welding or by a T-type special connector.

5. The multi-bus wiring structure for a large AGV vehicle body base plate as described in claim 1, 2, 3, or 4, characterized in that, The main line and branch lines are shielded twisted pair cables, and the shielding layer of the shielded twisted pair cables is a double layer of aluminum foil and braided mesh.

6. The multi-bus wiring structure for a large AGV body base plate as described in claim 3, characterized in that, The anti-interference unit: Termination resistors are set at the physical start and physical end of each of the aforementioned buses; Bias resistors are set at the host end of each of the buses, and the host end is connected to the main controller; An electrical isolation module is installed at each node of the bus.

7. The multi-bus wiring structure for a large AGV body base plate as described in claim 1, characterized in that, The different buses are placed in independent wire slots or in cavities separated by metal partitions in the same wire slot, and the spacing between the wire slots of adjacent buses is not less than 10mm.

8. A wiring method for a multi-bus wiring structure for a large AGV body substrate as described in any one of claims 1-7, characterized in that, Includes the following steps: S1. Divide the nodes on the substrate into several functional groups; S2. Plan the serpentine path for each bus in each of the aforementioned functional groups; S3. Connect each branch line of the bus to the main line; S4. Install terminating resistor.

9. The wiring method for a multi-bus wiring structure for a large AGV body substrate as described in claim 8, characterized in that, The substrate is provided with a power harness, and the distance between the bus and the power harness is not less than 30cm.

10. The wiring method for a multi-bus wiring structure for a large AGV vehicle body substrate as described in claim 8, characterized in that, The bus is an RS485 bus, and the support control group and the indicator power group of the functional group each include three RS485 buses.

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